CircleBack - Contact sync application.
FullContact Card Reader - Automagically scan biz cards into LinkedIn/Gmail contacts
Cisdem ContactsMate 4.2.0 - Cisdem ContactsMate: Sync, Create, find, manage, group, fix, and export your Contacts. Try it now!
Clearbit Connect - Clearbit Connect is a free extension that surfaces actionable information on the people who email you.
Google Contacts - Google Contacts is Google's contact management tool that is available in its free email service Gmail, as a standalone service, and as a part of Google's business-oriented suite of web apps Google Apps.
ZoomInfo - ZoomInfo is a B2B database providing detailed business information on people and companies.